Pelargonium coronopifolium is a
diploid with a
base chromosome number of 10 (2n=20). It is an upright, herbaceous
subshrub with main stems of up to high, that are rough under the level of the leaves because of the remains of old leaves and stipules. A plant may sprout several stems from the underground rootstock. All above-ground parts are covered in short hairs that are pressed stifly against the surface, and fewer
glandular hairs, except for the
pistils, stamens, staminodes, petals, and the inside of the sepals. The leaves are green to slightly greyish in colour, with a flat to V-shaped
leaf blade that has a
linear to narrowly
elliptical outline, usually long (full range ), and wide (rarely up to ). It gradually narrows into the
petiole, has a short sharp tip, and the margin is entire or has irregular teeth near the tip. The leaf stem is shorter than the leaf blade, long (rarely up to ), with a groove on the upper side. At the leaf base are two reddish-brown, awl-shaped stipules of long and wide. The
inflorescence stalks are (rarely up to ) long and each carry two or three, sometimes one or four,
zygomorphic flowers on (rarely up to ) long
flower stalks. Each flower has 5 green to reddish-brown
sepals that are merged into a tube at base about ¼ as long as the pedicel, are oval in outline, long and and with a pointy tip. Each flower has 5 white, pink or purple
petals. Two petals that are usually pointing upwards are long and wide, consisting of a
teardrop-shaped part (or
plate) at the top with darker markings, and a narrow basal part (or
claw) with side extensions (or ears). Three petals usually pointing down or forwards are without markings, elliptic in outline with a narrow claw, long and wide. Each flower has 2 long, 2 medium and 1 short fertile stamens topped with anthers with yellow to orange
pollen (best checked in the bud), and 5 infertile, glabrous and flattened
staminodes, two of which are sometimes slightly bent backwards. At their base, the filaments of the stamens and staminodes are merged into a column of long. The storkbill-shaped fruit eventually splits into 5
mericarps each with a capsule long containing a single seed and tail of long.
Differences with related species P. coronopifolium can be distinguished from
P. caespitosum which usually has only 4 petals (not always 5), a hardly developed hypanthium (not 2-8 mm long), stamens reaching below the anterior petals (not above), and leaf stalks than may me longer or shorter than the leaf blade (not leaf stalk always shorter). In
P. oenothera the claws of the largest upwardly directed petals lack lobes and the plate is flat (not claws of the upper petals eared and not plate flat or folded forwards).
P. tricolor has leaf stalks that may me longer or shorter than the leaf blades and the upper petals have three differently colours due to warty spots (not just one colour and without warty spots), as well as upper petal claws without ears and plates flat.
P. elegans has leaf stalks longer than the leaf blades (not shorter), upper petal claws without ears and plates flat (not with ears and plate flat ore folded) and 7 fertile stamens (not just 5, check in fresh flowers, anthers are quickly shed).
P. capillare has leaf stalks always longer than the leaf blades (not shorter), the upper petals have two different colours due to warty spots (not unicoloured without warty spots), and 7 fertile stamens (not just 5).
P. ovale has 3 straight and 2 short, hook-shaped staminodes, and leaf stalks longer than leaf blades (not 5 straight staminodes and shorter leaf stalks). == Taxonomy ==